1. Field of the Invention
The present invention relates to a drive control device for a floppy disk housed in a case provided with cleaning liners.
2. Description of the Related Art
Heretofore, with 3.5-inch floppy disk systems by way of example, storage mediums, that is, floppy disks, are housed in hard cases made of plastic. The case in which a disk is housed is usually called the cartridge. The storage medium is inserted into or ejected from a floppy disk drive (FDD) as it is housed in a case. The cartridge is provided with head windows through which a magnetic head can be brought into contact with the storage medium and shutters for closing the head windows.
Since such a storage medium is housed in a case, it is usually difficult for dust to adhere to the surface of the storage medium. But, a user might open the shutter of the cartridge by hand when it is not loaded into the disk drive. Dust might thus adhere to the storage medium in that event. When the cartridge is loaded into the disk drive, the shutter is opened by internal mechanisms. At this point, dust stirred up by vibration resulting from loading of the cartridge into the disk drive might adhere to the surfaces of the storage medium which are exposed in the head window areas.
Therefore, cartridges having inside cleaning liners which are in contact with both sides of the disk are used with conventional 3.5-inch floppy disk drives. Owing to the cleaning liner, the dust entering through the head window and adhering to the surface of the storage medium can be removed. It is because the storage medium rotates that the dust adhered to the surface of the storage medium can be removed by the cleaning liner.
When a storage medium is read from or written to, its center of rotation must always be held at the same point. For this reason, the storage medium is subjected to chucking when it is loaded in the disk drive. The chucking aligns two drive holes provided in the neighborhood of the center of the storage medium with two protrusions provided in the drive unit of the disk drive. In this case, the accurate chucking cannot be achieved unless two upper and lower magnetic heads are loaded and moderate friction between the disk and the heads occurs. Thus, the magnetic heads are loaded when the storage medium stops or does not rotate sufficiently immediately after the cartridge is loaded into the disk drive. That is, since the magnetic heads are loaded when dust adhering to the surface of the storage medium remains unremoved by the cleaning liners, a substantial pressure is applied to the dust. As a result, flaws might be produced in the storage medium, making its use impossible. Moreover, flaws might also be produced in the magnetic heads, thereby decreasing their life.